Requiring reporting of negative drug trial results
This is a very interesting question to have asked the public. My feeling is that the other 18% probably didn't understood the ramifications of such a subtle rule or it would have been 100% in favor.
A problem that has long affected the medical literature is what we call "publication bias". This is the selective publication of interesting studies, outcomes which are usually beneficial results from intervention trials. For example, if a drug is found to be effective at treating a particular condition, it is more likely to be published than if it is found to have no benefit.
Journals don't like reporting negative results because they're not sexy enough. Of course if the study demonstrates a deleterious effect of the drug, then that would be a sexy result and likely be published!
However, there is a more sinister reason for publication bias. When drug companies provide financial support for a clinical trial of one of their drugs and the results show no benefit, it may try to block the submission and therefore publication of the study. Technically, submission of the article would be at the discretion of the principle investigator (PI). But the thought of cutting off a future funding source may induce the PI to not submit.
One proposed solution to this problem would be to establish a registry for all studies regardless of the results. Outcomes and results would then have to be reported (and would be accessable by a medical literature search engine (such as www.pubmed.gov, the database maintained by the National Library of Medicine).
Obviously the drug companies would not be in favor of this and some people might argue about the intervention of big government in privately funded research. I don't believe that this is a valid argument in that there is clearly an overiding public interest in such a registry. Government is already involved in any study that uses human subjects at present. Mandating the public reporting of results of such studies seems like a very small additional burden.